PHYSIOLOGY OF MUSCLE 429 



CHAPTER XX 



THE MUSCULAR SYSTEM 



PHYSIOLOGY OF MUSCLE— CUTANEOUS MUSCLES— MUSCLES OF THE HEAD— ANTERIOR 

 MAXILLARY REGION— MUSCLES WHOSE OFFICE IT IS TO MOVE THE LOWER JAW — 

 MUSCLES OF THE EXTERNAL EAR — EXTERNAL MUSCLES OP THE EYELIDS — OCULAR 

 REGION — MUSCLES OF THE TONGUE — MUSCLES OF THE PHARYNX — LARYNGEAL REGION 

 — PALATINE REGION — SUPERFICIAL MUSCLES OF THE NECK AND TRUNK — LATERAL 

 CERVICAL REGION — INFERIOR CERVICAL REGION — SUPERIOR CERVICO-OCCIPITAL REGION 

 — INFERIOR CERVICO-OCCIPITAL REGION — MUSCLES CONNECTING THE SCAPULA WITH 

 THE HEAD, NECK, AND CHEST— MUSCLES OP THE THORAX — DORSAL REGION— MUSCLES 

 OF THE ABDOMEN — SUPERFICIAL ABDOMINAL REGION — DEEP ABDOMINAL REGION — 

 PELVIC REGION — MUSCLES OF THE FORE EXTREMITY — EXTERNAL SCAPULAR REGION 

 — ANTERO-INFERIOR SCAPULAR REGION — THE INTERNAL SCAPULAR REGION — POSTERO- 

 EXTERNAL SCAPULAR REGION — THE ANTERO-EXTERNAL HUMERAL REGION — THE 

 POSTERO-INTERNAL HUMERAL REGION — MUSCLES OF THE ARM AND FORE-LEG — MUSCLES 

 OF THE HAUNCH — GLUTEAL REGION — EXTERNAL ILIO-FEMORAL REGION — ANTERIOR II lO- 

 FEMORAL REGION— INTERNAL ILIO-FEMORAL REGION— THE DEEP MUSCLES OF THE ILIO- 

 FEMORAL REGION— ANTERIOR FEMORO-CRURAL REGION— POSTERIOR FEMORO-CRURAL 

 REGION. 



PHYSIOLOGY OF MUSCLE 



With trifling exceptions the whole of the movements of the body and limbs 

 are performed by the agency of that peculiar substance, known in our butchers' 

 shops as " flesh," and recognized by anatomists as muscular tissue. This 

 constitutes the chief bulk of the soft parts external to the three great 

 cavities (the cranial, thoracic, and abdominal), and in the half-starved subject 

 of the knacker or highly-trained race-horse, in which the fat has almost 

 entirely disappeared, the ordinary observer will detect nothing but muscles 

 (with their tendons) and bones beneath the skin covering the limbs. On the 

 trunk they are spread out into layers varying in thickness, sometimes inter- 

 rupted by flat tendons, so as to form, at the same time, a protection to the 

 organs within, easily capable of extension or contraction, and a means of 

 moving the several parts upon each other. 



Tendons resemble ligaments in being composed of white fibrous tissue, 

 described at page 393. They serve to connect muscle with bone, and are 

 useful as affording an agent for this purpose of much less compass than 

 muscle itself, and also of a structure not so easily injured by external 

 violence. Thus they are generally met with around the joints, the muscular 

 substance chiefly occupying the space between them. There are three 

 varieties of tendon. L Funicular, consisting of cord-like bands ; 2 Fasci- 

 cular, including bands of a flatter and more expanded nature ; and 3. 

 Ajwneurotic, which are membranous, and are chiefly met with around the 

 abdomen. The fibres are firmly attached to the bones, which generally 

 present rough surfaces for this purpose, and are also closely incorporated 

 with the periosteum. This union is so strong that it very rarely gives way; 

 and when extreme violence is used, either the bone itself breaks, or the 

 tendon snaps in its middle. Tendons are non-elastic, 



